Electronic device serving to supply a load with constant voltage pulses

ABSTRACT

An electronic device for supplying a load with constant voltage pulses, in which an oscillator connected to a source of electrical energy is used to charge periodically a main capacitor which is then discharged in the load with the aid of a thyristor. An auxiliary capacitor, when it is charged at a certain voltage, controls the blocking of the oscillator, which is then re-started upon the closing of an electronic switch which causes the discharge of the auxiliary capacitor, which discharge ignites the thyristor, across which the main capacitor discharges in the load. The device is suitable for supplying the primary of an ignition coil of an explosion engine.

United States Patent 1191 1, 1111 3 918 425 Best Available Copy Pulzer 5] Nov. 11, 1975 [5 ELECTRONIC DEVICE SERVING TO 3,560,833 2/1971 Oishi et a1. 123/148 E x SUPPLY A LOAD WITH CONSTANT 3,583,378 6/1971 Pattee 123/148 E 3,605,714 9/1971 Hardin et a1. 123/148 E VOLTAGE PULSES 3618,580 11/1971 Dogadko 123/148 E [75] Inventor: Jean-Bernard Pulzer, Neuchatel, 3,639,826 2/1972 Grundbergl. 315/209 CD X Switzerland 3,677,253 7/1972 Oishi et a1... 123/148 E 3,687,123 8/1972 Minks 123/148 E 1 Asslgneei 59190 la cheuX-dc-Fonds La 3,692,009 9/1972 lssler 123/143 E Chaux-de-Fonds, Switzerland 3,721,224 3/1973 Del Zotto.... 123/148 E 3.722.489 3/1973 Howard 1 123/148 E [22] Sept 1973 3,740,589 6/1973 Minks 1. 123/148 E x [21] Appl. No.: 400,143

Primary E.\'a/77inerCharles J. Myhre Assistant Examiner-Tony Argenbright [3O] Forelgn Apphcatlon Prlomy Data Attorney, Agent, or Fir/71Stevens, Davis, Miller &

Sept. 25, 1975 Switzerland 14070/72 M h [52] US. Cl ..123/l48 E; 123/148OD;

315/209 CD; 209 T [57] ABSTRACT [51] Int. C1. F02P 3/06 An r ni device for supplying a load with con- [58] Field of Search 123/148 E; 315/209 SC, stant voltage pulses, in which an oscillator connected 315/209 CD, 209 T, 209 R; 307/275; 328/67; to a source of electrical energy is used to charge peri- 333/113 A odically a main capacitor which is then discharged in the load with the aid of a thyristor. An auxiliary ca- [56] References Cited pacitor, when it is charged at a certain voltage, con- UNITED STATES PATENTS trols the blocking of the oscillator, which is then restarted upon the closing of an electronic switch which 2: 3;? 315/ 22 3 causes the discharge of the auxiliary capacitor, which 3 310 723 3/1967 56111115212111 11111171237148 E X discharge ignites the thyristor across which the main 3:334:619 8/1967 Penn 315/209 sc x Capacitor discharges in the lead- The device is Suitable 3,418,988 12/1968 Lewis et a1. 123/148 E fer pp y the P y Of an ignition coil of an 3,487,822 1/1970 l-lufton et a1.. 315/209 CD X plosion engine.

3,496,921 2/1970 Boyer 123/148 E 3,546,528 12/1970 Fisher 123/148 E x 9 Clam, 1 Drawmg Flgure ELECTRONIC DEVICE SERVING TO SUPPLY A LOAD WITH CONSTANT VOLTAGE PULSES The present invention relates to an electronic device for supplying a load with constant voltage pulses, comprising an oscillator, the oscillations of which are used to charge a capacitor which is then discharged across the load by means of an on/off device.

In such a device, it is necessary to have a circuit which detects the attainment of a desired charging voltage on the capacitor for interrupting the operation of the oscillator when this charging voltage is reached in order to guarantee a constant discharge voltage, i.e., one independent of voltage supplied to the device from a power supply.

Devices of this type are known which utilize the voltage of the capacitor, or part of it, to actuate a circuit which blocks the oscillator. The on/off devices used therein is generally a thyristor. These systems have the drawback of causing a slow discharge of the capacitor, and hence they require a periodical re-starting of the oscillator even if the thyristor has not been ignited. Furthermore, it may happen that, at extreme temperatures, the thyristor has a too long a conduction time, which keeps the oscillator from operating normally.

It is the aim of the present invention to eliminate I these shortcomings.

A further object of the invention is the use of this device to suitably feed the primary of an ignition coil of an explosion engine.

The device according to the invention is characterized in that the charge of an auxiliary capacitor controls the blocking of the oscillator, which is then restarted by the closing of an electronic switch which causes the discharge of the said auxiliary capacitor in order to ignite the thyristor, this thyristor being preferably equipped with an inductive element in order to facilitate extinguishing it. I r I When used to supply an ignition coil of an explosion engine, these devices are connectedto a control member actuated by the engine, to the said primary of an ignition coil, and to the battery. When the supply cables are too long, or if the attachment of the device does not provide very good contact with the ground of the vehicle, interference pulses may be picked up by the cable connected to the control member. These pulses are due to the operation of the oscillator, which absorbs sizable current peaks. On the other hand, the use of a mechanical circuit breaker for controlling the device requires a circuit provided with an appropriate filter in order to suppress the rebound effects.

In order to eliminate these drawbacks as well, the device according to the invention is also characterized in that the closing of the electronic switch is brought about via a control, circuit which is blocked during the operation of the oscillator and operated by a member actuated by the engine.

The following description illustrates, with reference to the accompanying diagram, an embodime nt of the device and of its use according to the invention. i

This embodiment is intended tobe placed on an engine designed for aconventional ignition assembly, i.e., having an ignition coil 4 and a circuit breaker 3. This circuit breaker comprises a fixed contact 3a and a movable contact 3b actuated by the rotation of the engine which causes the successive opening and closing of the contacts.

The ignition coil 4 comprises a high-voltage secondary 4b connected to a spark gap 5 (spark plugs) and a primary 4a through which, in the conventional ignition, there runs a current hatched by the circuit breaker 3. In the embodiment shown, the primary 4a, connected between the terminals C and D, is intended to carry the pulses generated by a device 7 which induce in the secondary 4b voltages sufficient to produce sparks at the spark plugs. These pulses are produced in the device 7 by the discharge of a capacitor C1 by means of a thyristor T7, and they are applied to the primary 4a of the ignition coil across an inductive element 8. This element, consisting of a coil L in parallel with a resistor R8, is intended to facilitate extinguishing the thyristor T7. The circuit which produces the activation of the thyristor T7 will be described in detail below.

The charging of the capacitor C1 is achieved via an oscillator circuit. For this purpose, the device 7 comprises besides various other circuit components, a transformer 6 with a primary 6a, and two secondaries 6b and 60, respectively. The secondary 6c of the transformer 6 is connected to the ground, on the one hand, and to the one electrode of this capacitor C1 by a diode D1 on the other hand. The other electrode end of this capacitor C1 is connected to an output terminal C, which is connected in turn to the ground by a diode D2 in parallel with the primary 4a of the ignition coil.

The device is powered by a battery 1 connected to a positive power supply terminal A via a main supply contact 2. The voltage of this battery is applied to the primary 6a of the oscillator transformer through a transistor T2. The base of the transistor T2 is connected to the emitter of a transistor T1, the collector of which is connected to an intermediate tap of the primary 6a, and the base of which is connected to one end of the secondary 6b for being supplied a feedback (reaction) voltage. The other end of the secondary winding 6b is connected to the ground, on the one hand, by a resistor R14, and to a point E, on the other hand, across the resistor R15 which supplies a bias voltage to the base of the transistor T1 for the starting of the oscillator. During the operation of the oscillator, (to be described in more detail further on) a positive voltage is periodically obtained at the base of this transistor T1, which voltage causes the transistors T1 and T2 to conduct. During the alternation when the transistors T1 and T2 are blocked, this base would carry a negative voltage, proportionate to the voltage of the secondary 60 used to charge the capacitor C1. However, the use of a diode D4 connected between the ground and the base of the transistor T1 prevents this negative voltage from appearing with a large value, thus protecting the base of this transistor, and also making it possible to recuperate this voltage at the other end of the winding 6b, in order to charge, across a diode D3, an auxiliary capacitor C2 intended to monitor the blocking of the oscillator.

The blocking of the oscillator is effected by a transistor T3, the collector of which is connected to the base of the transistor T1, and the emitter to the ground. The base of this transistor T3, having a resistor R11 connected to the ground, is connected to the positive power supply terminal A by a thyristor T5 across a resistor R13. The thyristor T5 is switched on when a capacitor C2 becomes charged (in a manner which will be described further on) and causes the transistor T3 to conduct. For that purpose, the gate of the thyristor T5, also connected to the base of the transistor T3 via a resistor R12, is connected to the capacitor C2 by a Zener diode Z1. A control pulse at the gate of a thyristor T6 causes the discharge of the capacitor C2 across a resistor R9, the thyristor T6, the gate of the thyristor T7 in parallel with the resistor R7, and the inductive element 8. This discharge controls the ignition of the main thyristor T7, on the one hand, and the extinguishing of the thyristor T5, on the other hand, by applying to the anode of the latter a negative pulse via a capacitor C3 connected between the anodes of the thyristors T and T6. By using the discharge of the capacitor C2 to switch on the main thyristor T7, a very energetic pulse becomes available which remains constant even when there are significant fluctuations of the supply voltage. However, at high temperatures, the elements connected to the capacitor C2 may exhibit small leakage currents which might discharge the capacitor and hence prevent re-starting of device 7 after a long interruption of the oscillator. In order to avoid this drawback, the capacitor C2 is connected to the positive terminal A by a high-value resistor R which thus makes it possible to compensate for the possible leakage currents.

The control pulse of the thyristor T6, applied by a diode D7 to the gate of the thyristor T6, which comprises a resistor R6 between its gate and its cathode, is obtained when the contacts of the circuit breaker 3 open by the charging of a capacitor C4 across a diode D6 and the resistors R1, R2, R4 and R5 connected in series with the capacitor. A capacitor C5, connected between the resistors R1 and R2, on the one hand, and to the ground, on the other hand, operates to prevent voltage peaks produced at the terminal A from generating starting pulses across the capacitor C4. The closing of the contacts of the circuit breaker 3 enables the capacitor C4 to discharge across the resistors R3, R5, and R4. The time constant of this circuit is determined in such a way that the rebounds of the contacts 3a and 3b cannot cause spurious operations. On the other hand, the pulses supplied by this control circuit for the ignition of the thyristor T6 are short-circuited by a transistor T8 during the operation of the oscillator. To this end, the collector of the transistor T8 is connected to the junction between the resistor R4 and the anode of the diode D7, the emitter of this transistor T8 being grounded. The base of this transistor T8, connected to the ground via a resistor R16, is also connected by a resistor R17 to a point E. During the operation of the oscillator, i.e., when the thyristor T5 is blocked, the positive supply voltage is applied to the point E across a resistor R13 and a diode D5 connected between the anode of the thyristor T5 or the point E. For the time -when thyristor T5 is blocked, the voltage on point E is stabilized by a Zener diode Z2 connected between the point E and the ground, and it supplies the energizing voltage for the transistor T8, as well as the bias voltage, necessary for the starting of the oscillator, to the transistor T1. On the other hand, when thyristor T5 is in the conduction state, the voltage at point B becomes very low, the Zener diode Z2 thus being inoperative. Transistor T8 is not energized, thus preventing the control circuit for thyristor T6 from being short-circuited, and there is no bias voltage for starting the oscillator.

The operation of the device will now be described in more detail. A basic distinction is made between two conditions, viz, an oscillating condition during which the capacitor C1 charges up to the desired voltage and the transistor T8, in the conductive state, prevents by means of short-circuiting the sending of any driving pulse from the thyristors T6, T7; and a holding condition during which the capacitor C1 is charged at the desired voltage and the transistor T8 does not prevent the passage of a driving pulse. The holding condition is maintained until a driving pulse is actually applied to make the thyristors T6 and T7 conductive and to discharge the capacitor C1 across the primary winding 4a of the ignition coil.

It should be noted first of all that the two capacitors C1 and C2 charge and discharge in unison. At the moment of a discharge, the capacitor C2, assumed to have been previously charged, discharges across the resistor R9, the thyristor T6, the resistor R7, and the parallel network of the resistor R8 and the inductance L. The voltage drop in the resistor R7 creates a potential difference between the cathode and the gate of the thyristor T7, which becomes conductive, The capacitor C1 thus discharges across the thyristor T7, the parallel network RS/L, and the primary winding 4a of the ignition coil 4, no current then passing through the diode D2, which is biased at that moment in the blocking direction. When the capacitor C1 is completely discharged, its discharging current ceases, after the inductive element has briefly tended to maintain that current by supplying an induced electromotive force which very slightly charges the capacitor C1 in the reverse direction. When the current has ceased and the electromotive force induced in the inductance L has disappeared, this very slight reverse voltage on the capacitor C1 completely ensures that the thyristor T7 is extinguished.

However, as will be seen later on, the capacitor C1 soon recharges in the direct polarity; in any event, the slight reverse voltage which it takes on to extinguish the thyristor T7 is negligible compared with the voltage at which it charges in the direct polarity. Even before the capacitor C1 has finished discharging, or just at the moment when it finishes discharging at the latest, the capacitor C2 has likewise completely discharged across the aforementioned circuit. It will also be noted that at the moment when the capacitor C2 discharges, the voltage drop which abruptly takes place in the resistor R9 is transmitted by the capacitor C3 to the anode of the thyristor T5 which, although it may previously have been conductive, will in any case be restored to the non-conducting state by this negative pulse at its anode.

Starting from the above-mentioned conditions as they exist at the end of the discharge of the capacitors Cl and C2, namely, the non-conducting state of the thyristors T7, T6, and T5, the situation which will prevail in the device may be established on the basis of the diagram of the device. Because the capacitor C2 is discharged, the Zener diode Z1 will not allow any current topass. Thus there will be no voltage at the gate of the thyristor T5, which will remain in the non-conducting state in which it has been placed by the negative pulse at its anode. The absence of current through the thyristor T5 and through the Zener diode Z1 will ensure the presence of a ground potential at the base of the transistor T3 since no current will pass through the resistor R11. The transistor T2 will therefore be in the non-conducting state, which means that the transistor T1 will not necessarily be kept in the non-conductive state by the application of a ground potential to its base.

On the other hand, the non-conductive state of the thyristor T5 will allow the positive voltage to pass through the resistor R13 to the point E, where this positive voltage will be stabilized by the Zener diode 22. The voltage divider R15, R14 will therefore supply a bias voltage to the secondary winding 6b of the transformer 6, and thereby to the base of the transistor T1. Moreover, this bias voltage will tend to start charging the capacitor C2 via the diode D3. The voltage at the base of the transistor T1, originally just equal to the threshold voltage of the diode D3, will soon become sufficient for a current to pass through the base-emitter junctions of the two transistors T1 and T2. From that moment on, a current will pass through the primary winding 6a of the transformer 6, the result of which will be, taking into account the polarities of the windings indicated on the figure by dots, the increase of the positive potential at the base of the transistor T1. The feedback gain of the circuit comprising the two transistors T1 and T2 and the two windings 6a and 6b of the transformer being greater than 1, the increasing effect of the current will be cumulative until saturation of the transformer, after which the decrease of the induced voltage in the windin g 6b due to that saturation will bring about a decrease of the current in the transistors T1 and T2, thus in the primary winding 6a, and this will reverse the induced voltage in the secondary winding 6b. There will once more be a cumulative decreasing effect continuing until interruption of the current in the primary winding 6a. As soon as this current has ceased to circulate and to decrease, the bias voltage will reappear at the base of the transistor T1, the transistors T1 and T2 will become conductive again, and the cycle will be repeated. What is involved is indeed the classic operation of an oscillator.

It will be noted that the connection of the collector of the transistor T1, not at the same point as the collector of the transistor T2, but at an adjacent tapping point, does not appreciably alter the Darlington configuration which is, in fact, formed by the transistors T1 and T2. This connection of the collector of the transistor T1 to an intermediate tapping point is simply intended to compensate for the voltage drop equal to twice the threshold voltage for the current passing through the transistor T1, this improving the operation of the two transistors. It would be quite possible, however, to have only one high-gain transistor in place of the transistors T1 and T2.

During the operation as an oscillator which has just been considered, the secondary windings 6b and 6c are subject to a sequence of alternately positive and negative half-periods. As may be deduced from the arrangement of the dots near the ends of the windings 6a, 6b, and 6c on the figure, during the half-period when the voltage is positive at the base of the transistor T1, the voltage is negative at the anode of the diode D1, so that no current passes through the latter. During the other half-period, on the contrary, a current will pass through the diode D1 and thus come to charge the capacitor C1 across the diode D2 in parallel with the primary winding 4a of the ignition coil. Simultaneously, there is a negative voltage at the base of the transistor T. This voltage, however, cannot become more negative than the threshold voltage of the diode D4; and in return, a positive voltage appears at the anode of the diode D3, as well as at the junction points between the resistors R15 and R14. This voltage will charge the capacitor C2 via the diode D3, and since the two capacitors C1 and C2 charge during the same half-period and combine their effects to condition this half-period, the two capacitors C1 and C2 will charge correlatively, i.e., the voltage on these two capacitors will increase in the same way, taking into account a proportionality factor due to the number of turns of the windings. The voltage at the terminals of the capacitor C2 will therefore be an exact counterpart of the voltage at the terminals of the capacitor C1 but and this is particularly important without there being any charge derivation drained from the capacitor C1. This effect of complete galvanic separation between the capacitor supplying the output discharge (C1) and the capacitor enabling the charge to be checked (C2) constitutes an important and hitherto unknown advantage of the device described here.

During the oscillating condition which has just been described, the capacitor C2, the counterpart of the capacitor C1, gradually charges, so that the voltage at the terminals of the Zener diode Z1 finally exceeds the Zener voltage thereof, and a current begins to pass through this Zener diode. This current creates a voltage drop in the resistor R12, causing the thyristor T5 to go into the conductive state. From that moment on, the transistor T3, which receives a positive potential at its base, becomes conductive and short-circuits the transistors T1 and T2; so that the oscillation stops, while the capacitor C1, free of any derivation, retains the charging voltage it has reached at that moment. At the same time, the conduction of the thyristor T5 causes the voltage at the point E to drop and substantially nullifies the voltage at the anode of the diode D3, as well as the voltage at the base of the transistor T8.

During the oscillating situation described above, the transistor T8 was made conductive by the positive voltage at the point E, so that the anode of the diode D7 was substantially kept at low impedance with respect to the ground potential. The opening of the contact 30, 3b

causes a positive voltage jump at the point E and tends to transmit a positive pulse across the diode D6 and the capacitor C4. As long as the transistor T8 was in the conductive state, such a positive voltage pulse was short-circuited, this voltage being absorbed in the resistor R4. Thus during the "operation of the oscillator, no positive pulse could be applied to the anode of the diode D7, and hence to the gate of the thyristor T6, so that neither a pulse which might have been given by opening the contact 3a, 3b, nor an interference pulse which might have occurred at the capacitor C4, could have caused the thyristor T6 to ignite. This is important because precisely what has been established is that during the operation of the oscillator, strong current peaks circulate in the conductor, and there may very well be interfering voltage pulses according to the way the grounding is done.

Starting from the moment when the oscillating condition has ceased, to make way for the holding condition, the transistor T8 is no longer conductive, and a positive pulse, due to the breaking of the contact 3a, 3b and applied via the diode D6 and the capacitor C4, can pass through the diode D7 to switch on the thyristor T6. This will take place at the appointed time, at the moment determined by the operation of the breaker contact 3; and as soon as the thyristor T6 is ignited, the process of the discharge of the capacitor C2 across the thyristor T6 and of the capacitor C1 across the thyristor T7 will be repeated, supplying to the primary winding 4a of the ignition coil a pulse of precisely determined voltage which will always be the same (the voltage at the capacitor C1 at the moment when the oscillation ceases) whatever may be the fluctuations of 7 the power supply voltage at the supply terminal A.

The maximum ignition-pulse repetition frequency for an explosion engine practically never exceeds 400 to 500 pulses per second. In a prototype which has been produced, the oscillating frequency. reached kc/s, which means that in the most unfavorable case (eg, an 8-cylinder engine running at extremely high speed), there are still more than 10 half-periods available to charge the capacitors. Thus the ignition sparks remain constant, not only despite possible fluctuations of the supply voltage (battery voltage), but also as a function of the more or less rapid pulse sequence required, and this up to the highest values which occur in practice for automobile engines.

By virtue of the excellent quality of the ignition which it provides, the device according to the present invention, one embodiment of which has just been de scribed, but numerous other embodiments of which would likewise be conceivable, makes possible a significant improvement in the efficiency of explosion engines under their various operating conditions.

What is claimed is:

1. An electronic device including means for supplying a load with constant voltage pulses, said device comprising:

power supply terminals connectable to a source of electrical energy,

an oscillator connected to said power supply terminals, comprising at least one active electronic element and a transformer having a plurality of windings forming at least one primary winding in cooperative relationship with said active element and at least one secondary winding electrically separated from said active electronic element,

switching conditioning means for switching said oscillator selectively into inoperative and operative conditions,

a first capacitor,

first rectifier means connecting said first capacitor to said secondary winding of said transformer for charging said first capacitor during said operative condition of said oscillator,

control input receiving means settable in relation to external control means and to receive command signals therefrom for controlling occurrences of said constant voltage pulses,

output terminal means connectable to said load,

main controlled electronic means comprising an on/ off device in series with said first capacitor in a discharge circuit thereof, connected for operating under control of said control input receiving means, and for causing said first capacitor to discharge through said discharge circuit across said output terminal means upon receiving one of said command signals,

a second capacitor,

second rectifier means connecting said second capacitor to a winding of said transformer separate from said secondary winding to which said first capacitor is connected,

auxiliary controlled electronic means connected for operating under control of said control input receiving means and causing said second capacitor to discharge upon receiving one of said command signals,

voltage level detecting means connected to said second capacitor for detecting the attainment of a predetermined charging voltage thereon,

said first and said second rectifier means simultaneously and homologously charging said first and said second capacitors,

said main and said auxiliary controlled electronic means simultaneously causing said first and said second capacitors to homologously discharge,

said first rectifier means and said main controlled electronic means preventing any current from flowing through said first capacitor during said inoperative condition of said oscillator with said on/- off device in the off condition,

and said switching conditioning means being responsive to said voltage level detecting means for switching said oscillator to said inoperative condition, and being responsive to one of said main and auxiliary controlled electronic means for switching said oscillator to said operative condition.

2. A device according to claim 1, wherein said load is the primary winding of an ignition coil of an explosion engine, and wherein said control input receiving means comprises an inhibiting circuit connected for operating under con trol of said switching conditioning means for preventing said command signals, as well as any spurious signal which might be received by said control input receiving means, from causing said main and said auxiliary controlled electronic means to operate for causing said first and second capacitors to discharge.

3. A device according to claim 1, wherein said main controlled electronic means comprises a first thyristor as said on/off device.

4. A device according to claim 3 wherein said switching conditioning means comprises:

a conditioning thyristor connected to be conducting for setting said oscillator in the inoperative condition and to be non-conducting for setting said oscillator in the operative condition,

and an oscillator inhibiting transistor connected to be switched on by a current flowing through said conditioning thyristor in the on state thereof, said oscillator inhibiting transistor establishing, in the switched-on state, a short circuit over said active electronic element of said oscillator.

5. A device according to claim 4, wherein said first rectifier means comprises a diode connected between said first capacitor and said secondary winding separate from said active electronic element,

said second rectifier means comprises a diode connected between said second capacitor and a winding of said transformer connected to said active element, and

said voltage level detecting means comprises a Zener diode connected between said second capacitor and the gate of said conditioning thyristor for causing it to switch on when said second capacitor becomes charged at a voltage equal to the Zener voltage of said Zener diode.

6. A device according to claim 5, wherein said auxiliary controlled electronic means comprises an auxiliary thyristor, having its gate connected to said control input receiving means for causing said auxiliary thyristor to conduct upon receiving one of said command signals, and having its anode-cathode path connected in a circuit with said second capacitor, which circuit includes a resistor connected between the gate and cathode of said first thyristor for causing the current passing 9 through said auxiliary thyristor upon receiving one of said command signals to switch on said first thyristor, and thus causing said first capacitor to discharge through said discharge circuit across said output terminal means.

7. A device according to claim 6, wherein said discharge circuit of said first capacitor includes an impedance member for ensuring said first thyristor is extinguished just after discharge of said first capacitor.

8. A device according to claim 6, wherein said switching conditioning means comprises a conditioning control capacitor interconnecting the anodes of said conditioning thyristor and said auxiliary thyristor for causing the switching-on of said auxiliary thyristor to extinguish said conditioning thyristor and thereby switching said switching conditioning means into a state which resets said oscillator into said operative condition.

9. A device according to claim 2, operating with a conventional mechanical circuit breaker, wherein said control input receiving means comprises,

a control input terminal connectable to said circuit breaker,

two resistors in series between said control input terminal and one of said power supply terminals,

a decoupling capacitor connected between the other of said power supply terminals and the point where said two resistors are connected,

an input diode and an input resistor connected in series between said control input terminal and said other power supply terminal,

an input transmitting branch comprising a capacitor and a resistor in series, said input transmitting branch having one end connected to the point where said input diode and said input resistor are connected, and another end connected in relation with at least one of said main and auxiliary controlled electronic means,

and an input inhibiting transistor controlled by said switching conditioning means for being selectively switched on and switched off, the emitter collector path of said input inhibiting transistor being connected between said other end of said input transmitting branch and one of said power supply terminals for causing, in its on state, a short-circuiting of said input transmitting branch, said short-circuiting preventing and pulses from being transmitted through said branch onto said main and auxiliary controlled electronic means.

l= l l 

1. An electronic device including means for supplying a load with constant voltage pulses, said device comprising: power supply terminals connectable to a source of electrical energy, an oscillator connected to said power supply terminals, comprising at least one active electronic element and a transformer having a plurality of windings forming at least one primary winding in cooperative relationship with said active element and at least one secondary winding electrically separated from said active electronic element, switching conditioning means for switching said oscillator selectively into inoperative and operative conditions, a first capacitor, first rectifier means connecting said first capacitor to said secondary winding of said transformer for charging said first capacitor during said operative condition of said oscillator, control input receiving means settable in relation to external control means and to receive command signals therefrom for controlling occurrences of said constant voltage pulses, output terminal means connectable to said load, main controlled electronic means comprising an on/off device in series with said first capacitor in a discharge circuit thereof, connected for operating under control of said control input receiving means, and for causing said first capacitor to discharge through said discharge circuit across said output terminal means upon receiving one of said command signals, a second capacitor, second rectifier means connecting said second capacitor to a winding of said transformer separate from said secondary winding to which said first capacitor is connected, auxiliary controlled electronic means connected for operating under control of said control input receiving means and causing said second capacitor to discharge upon receiving one of said command signals, voltage level detecting means connected to said second capacitor for detecting the attainment of a predetermined charging voltage thereon, said first and said second rectifier means simultaneously and homologously charging said first and said second capacitors, said main and said auxiliary controlled electronic means simultaneously causing said first and said second capacitors to homologously discharge, said first rectifier means and said main controlled electronic means preventing any current from flowing through said first capacitor during said inoperative condition of said oscillator with said on/off device in the off condition, and said switching conditioning means being responsive to said voltage level detecting means for switching said oscillator to said inoperative condition, and being responsive to one of said main and auxiliary coNtrolled electronic means for switching said oscillator to said operative condition.
 2. A device according to claim 1, wherein said load is the primary winding of an ignition coil of an explosion engine, and wherein said control input receiving means comprises an inhibiting circuit connected for operating under control of said switching conditioning means for preventing said command signals, as well as any spurious signal which might be received by said control input receiving means, from causing said main and said auxiliary controlled electronic means to operate for causing said first and second capacitors to discharge.
 3. A device according to claim 1, wherein said main controlled electronic means comprises a first thyristor as said on/off device.
 4. A device according to claim 3 wherein said switching conditioning means comprises: a conditioning thyristor connected to be conducting for setting said oscillator in the inoperative condition and to be non-conducting for setting said oscillator in the operative condition, and an oscillator inhibiting transistor connected to be switched on by a current flowing through said conditioning thyristor in the on state thereof, said oscillator inhibiting transistor establishing, in the switched-on state, a short circuit over said active electronic element of said oscillator.
 5. A device according to claim 4, wherein said first rectifier means comprises a diode connected between said first capacitor and said secondary winding separate from said active electronic element, said second rectifier means comprises a diode connected between said second capacitor and a winding of said transformer connected to said active element, and said voltage level detecting means comprises a Zener diode connected between said second capacitor and the gate of said conditioning thyristor for causing it to switch on when said second capacitor becomes charged at a voltage equal to the Zener voltage of said Zener diode.
 6. A device according to claim 5, wherein said auxiliary controlled electronic means comprises an auxiliary thyristor, having its gate connected to said control input receiving means for causing said auxiliary thyristor to conduct upon receiving one of said command signals, and having its anode-cathode path connected in a circuit with said second capacitor, which circuit includes a resistor connected between the gate and cathode of said first thyristor for causing the current passing through said auxiliary thyristor upon receiving one of said command signals to switch on said first thyristor, and thus causing said first capacitor to discharge through said discharge circuit across said output terminal means.
 7. A device according to claim 6, wherein said discharge circuit of said first capacitor includes an impedance member for ensuring said first thyristor is extinguished just after discharge of said first capacitor.
 8. A device according to claim 6, wherein said switching conditioning means comprises a conditioning control capacitor interconnecting the anodes of said conditioning thyristor and said auxiliary thyristor for causing the switching-on of said auxiliary thyristor to extinguish said conditioning thyristor and thereby switching said switching conditioning means into a state which resets said oscillator into said operative condition.
 9. A device according to claim 2, operating with a conventional mechanical circuit breaker, wherein said control input receiving means comprises, a control input terminal connectable to said circuit breaker, two resistors in series between said control input terminal and one of said power supply terminals, a decoupling capacitor connected between the other of said power supply terminals and the point where said two resistors are connected, an input diode and an input resistor connected in series between said control input terminal and said other power supply terminal, an input transmitting branch comprising a capacitor and A resistor in series, said input transmitting branch having one end connected to the point where said input diode and said input resistor are connected, and another end connected in relation with at least one of said main and auxiliary controlled electronic means, and an input inhibiting transistor controlled by said switching conditioning means for being selectively switched on and switched off, the emitter collector path of said input inhibiting transistor being connected between said other end of said input transmitting branch and one of said power supply terminals for causing, in its on state, a short-circuiting of said input transmitting branch, said short-circuiting preventing and pulses from being transmitted through said branch onto said main and auxiliary controlled electronic means. 